Biomedical subjects

S Kanno

Publications and source records attributed to S Kanno.

At least 37 records · Page 2Linked to original sources

PubMed2001

Cyclohexane as an alternative vapor of carbon tetrachloride for the assessment of gas removing capacities of gas masks.

An alternative vapor was explored to replace carbon tetrachloride (CCl4) for testing breakthrough times of cartridges and canisters of gas masks in the National Approval Test of Respirators. Cyclohexane was single out as a candidate for the alternative vapor out of six vapors: trichloroethylene, n-pentane, n-hexane, n-heptane, toluene and cyclohexane from the viewpoints of similarity of vapor pressure and water-solubility to CCl4, lower toxicity than CCl4, and technical feasibility in generating an airflow of 30 L/min containing the vapor ranging from 300 to 5000 ppm. Breakthrough times of cartridges and canisters were examined by generating cyclohexane vapor in a test airflow of 30 L/min in comparison with CCl4 vapor under various test conditions with different vapor concentrations and relative humidities (RH). As the results, the breakthrough times of the cartridges and canisters for cyclohexane were found to almost coincide with those for CCl4 under all examined range of concentrations and RH. By an increase of humidity from 50% RH to 80% RH, the cartridges showed significant shortening of breakthrough times for both of CCl4 and cyclohexane, but the susceptibility of the breakthrough time of cyclohexane to humidity was also similar to that of CCl4. It was, therefore, concluded that cyclohexane can be recommended as the alternative vapor of CCl4 for testing the breakthrough times of gas mask cartridges and canisters in the National Approval Test.

Air Pollutants, Occupational↗

PubMed2001

Tsutsugamushi disease in Kanagawa Prefecture, Japan: clinical report of two cases and survey of other incidences in 1998.

Tsutsugamushi disease is characterized by the early appearance of a black crust at the bitten area and the subsequent development of macular or macropapular rush on the whole body with high fever. While treatment with tetracycline derivatives and chloramphenicols is effective, delayed diagnosis or inappropriate treatment will lead to fatality. In this report, we describe two typical cases of tsutsugamushi disease and discuss other incidences in Kanagawa Prefecture, Japan, in 1998. One of the present two patients was diagnosed to be a case of the new type by Kawasaki strain of Rickettsia tsutsugamushi, while responsible strain was not identified for the other case. Since the disease is spreading widely even to suburban areas, we emphasize the need to consider the possible diagnosis of tsutsugamushi disease in patients with generalized eruption and high fever.

Anti-Bacterial Agents↗

PubMed2000

Cellular responses and repair of single-strand breaks introduced by UV damage endonuclease in mammalian cells.

Although single-strand breaks (SSBs) occur frequently, the cellular responses and repair of SSB are not well understood. To address this, we established mammalian cell lines expressing Neurospora crassa UV damage endonuclease (UVDE), which introduces a SSB with a 3'-OH immediately 5' to UV-induced cyclobutane pyrimidine dimers or 6-4 photoproducts and initiates an alternative excision repair process. Xeroderma pigmentosum group A cells expressing UVDE show UV resistance of almost the wild-type level. In these cells SSBs are produced upon UV irradiation and then efficiently repaired. The repair patch size is about seven nucleotides, and repair synthesis is decreased to 30% by aphidicolin, suggesting the involvement of a DNA polymerase delta/epsilon-dependent long-patch repair. Immediately after UV irradiation, cellular proteins are poly(ADP-ribosyl)ated. The UV resistance of the cells is decreased in the presence of 3-aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase. Expression of UVDE in XRCC1-defective EM9, a Chinese hamster ovary cell line, greatly sensitizes the host cells to UV, and addition of 3-aminobenzamide results in almost no further sensitization of the cells to UV. Thus, we show that XRCC1 and PARP are involved in the same pathway for the repair of SSBs.

Animals↗

PubMed2000

Attenuation of myocardial ischemia/reperfusion injury by superinduction of inducible nitric oxide synthase.

BACKGROUND: Nitric oxide (NO) has been implicated as a mediator in myocardial ischemia/reperfusion (I/R) injury, but its functional properties have been conflicting. We investigated whether NO has a protective role against I/R injury. METHODS AND RESULTS: Using endothelial NO synthase knockout (eNOS KO) mice, inducible NOS KO mice, the NO donor S-nitroso-N-acetylpenicillamine (SNAP), and the NOS inhibitor N-iminoethyl-L-ornithine (L-NIO), we performed studies of isolated perfused hearts subjected to 30 minutes of global ischemia followed by reperfusion. After 60 minutes of reperfusion, nitrite levels in the coronary effluent in the SNAP and eNOS KO groups were significantly elevated compared with other groups. Immunoblot and immunohistochemistry showed that iNOS was markedly induced in the eNOS KO hearts. Under spontaneous beating conditions during reperfusion, increased NO activity was correlated with a prevention of the hyperdynamic contractile response and enhanced myocardial protection, as evidenced by a reduction in myocardial injury and infarct size. During prolonged reperfusion, SNAP-treated hearts were able to preserve contractile functions for 180 minutes, whereas L-NIO-treated hearts showed a sustained deterioration in contractility. CONCLUSIONS: NO protects against I/R injury by preventing the hyperdynamic response of isolated perfused hearts during early reperfusion. In the eNOS KO hearts, a paradoxical increase in NO production was seen, accompanied by a superinduction of iNOS, possibly due to an adaptive mechanism.

Animals↗

PubMed2000

Roles of two VEGF receptors, Flt-1 and KDR, in the signal transduction of VEGF effects in human vascular endothelial cells.

Vascular endothelial growth factor (VEGF) is a principal regulator of vasculogenesis and angiogenesis. VEGF expresses its effects by binding to two VEGF receptors, Flt-1 and KDR. However, properties of Flt-1 and KDR in the signal transduction of VEGF-mediated effects in endothelial cells (ECs) were not entirely clarified. We investigated this issue by using two newly developed blocking monoclonal antibodies (mAbs) against Flt-1 and KDR. VEGF elicits DNA synthesis and cell migration of human umbilical vein endothelial cells (HUVECs). The pattern of inhibition of these effects by two mAbs indicates that DNA synthesis is preferentially mediated by KDR. In contrast, the regulation of cell migration by VEGF appears to be more complicated. Flt-1 regulates cell migration through modulating actin reorganization, which is essential for cell motility. A distinct signal is generated by KDR, which influences cell migration by regulating cell adhesion via the assembly of vinculin in focal adhesion plaque and tyrosine-phosphorylation of focal adhesion kinase (FAK) and paxillin.

3T3 Cells↗

PubMed2000

Assembling of engineered IgG-binding protein on gold surface for highly oriented antibody immobilization.

The B-domain, which is one of IgG-binding domains of staphylococcal protein A, was repeated five times and a cysteine residue was introduced at its C-terminus by a genetic engineering technique. The resulting protein, designated B5C1, retained the same IgG-binding activity as native protein A. The B5C1 was assembled on a gold plate surface by utilizing a strong affinity between thiol of cysteine and a gold surface. IgG-binding activity of B5C1 on a gold surface was much higher than that of physically adsorbed B5, which lacks cysteine residue. Furthermore, antigen-binding activity of immobilized antibody molecules through the use of assembled B5C1 on a gold surface was about 4.3 times higher than that of physically adsorbed antibody molecules. Immobilization of highly oriented antibody molecules was realized with the engineered IgG-binding protein.

Antibodies↗

PubMed2000

Aberrations of the K-ras, p53, and APC genes in extrahepatic bile duct cancer.

BACKGROUND AND OBJECTIVES: The genetic alterations involved in extrahepatic bile duct (EHBD) cancer are poorly understood. Our aim was to identify aberrations of the K-ras, p53, and APC genes in EHBD cancer. METHODS: We investigated aberrations of these genes in 52 EHBD cancers using polymerase chain reaction (PCR) single-strand conformation polymorphism analysis, followed by direct sequence determination and a PCR restriction fragment length polymorphism assay. RESULTS: The K-ras, p53, and APC genes were mutated in 9.6%, 32.7%, and 0% of EHBD cancers, respectively. Loss of heterozygosity at the p53 and APC gene loci was identified in 15.6% and 38.5% of EHBD cancers, respectively. CONCLUSIONS: Our results suggest that an unknown suppressor gene on 5q other than the APC gene may be responsible for EHBD cancer.

Aged↗

PubMed2000

Signal transduction and transcriptional regulation of angiogenesis.

When quiescent endothelial cells (ECs) are exposed to angiogenic factor such as VEGF; ECs express proteases to degrade extracellular matrices, migrate, proliferate and form new vessels. However, the molecular mechanism of these events is not fully characterized yet. We are studying the signal transduction and transcriptional regulation of angiogenesis. We investigated the properties of two VEGF receptors, Flt-1 and KDR, by using two newly developed blocking monoclonal antibodies (mAbs), i.e., anti-human Flt-1 mAb and anti-human KDR mAb. VEGF elicited induction of transcription factor Ets-1 in human umbilical vein endothelial cells (HUVECs). This induction was mediated by the KDR/Flt-1 heterodimer and the KDR homodimer. The role of transcription factor Ets-1 in angiogenesis was further clarified. We established both high and low Ets-1 expressing EC lines, and compared angiogenic properties of these cell lines with a parental murine EC line, MSS31. The growth rate was almost identical among three cell lines. It appeared that gene expressions of matrix metalloproteinases (MMP-1, MMP-3, and MMP-9) as well as integrin beta 3 were correlated with the level of Ets-1 expression. As a result, the invasiveness was enhanced in high Ets-1 expressing cells and reduced in low Ets-1 expressing cells compared with parental cells, and high Ets-1 expressing cells made more tube-like structures in type 1 collagen gel. These results indicate that Ets-1 is a principle transcription factor converting ECs to the angiogeneic phenotype.

Animals↗

PubMed2000

Fluoride induces apoptosis by caspase-3 activation in human leukemia HL-60 cells.

Even though fluoride toxicity is increasingly being considered to be important, very little information is available on the mechanism of action of fluoride. In the present study, the toxicity of fluoride on human leukemia (HL-60) cells was investigated and the involvement of caspase-3 was also studied. Fluoride induced apoptosis in HL-60 cells in a dose- and time-dependent manner. Annexin staining and DNA ladder formation on agarose gel electrophoresis further revealed that HL-60 cells underwent apoptosis on exposure to 2-5 mM fluoride. Western blotting using polyclonal anti-caspase-3 antibody and mouse anti-human poly(ADP-ribose) polymerase (PARP) monoclonal antibody was performed to investigate caspase-3 and PARP activity. Fluoride led to the activation of caspase-3 which was evident by the loss of the 32 kDa precursor and appearance of the 17 kDa subunit. Furthermore, intact 116 kDa PARP was cleaved by fluoride treatment as shown by the appearance of a cleaved 89 kDa fragment. The results clearly suggest that fluoride causes cell death in HL-60 cells by causing the activation of caspase-3 which in turn cleaves PARP leading to DNA damage and ultimately cell death.

Apoptosis↗

PubMed2000

Ocular surface changes after excimer laser phototherapeutic keratectomy.

PURPOSE: To study the ocular surface disorder in patients with Avellino, granular, and lattice dystrophy, band keratopathy, and corneal leukoma before and after excimer laser phototherapeutic keratectomy. DESIGN: A prospective case-controlled study. PARTICIPANTS: A total of 45 eyes of 33 patients with superficial corneal opacities seen at Kobe Kaisei Hospital, Department of Ophthalmology, and 40 eyes of 20 normal control subjects were studied. INTERVENTION: The subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, tear film break up time (BUT), Schirmer test, tear film lipid layer interferometry, and conjunctival impression cytology. MAIN OUTCOME MEASURES: The patients and the control subjects were compared for prephototherapeutic keratectomy (PTK) tear function parameters, tear film lipid layer interferometry grade, goblet cell density, and conjunctival squamous metaplasia grade. Alterations of these parameters within 3 months after PTK were also looked for. RESULTS: The average pre-PTK corneal sensitivity and tear film break up time were lower in patients compared with control subjects before PTK. Tear film lipid layer interferometry grade and conjunctival squamous metaplasia grades were higher in the patients than the controls before PTK. All these parameters improved gradually and significantly after PTK. Goblet cell density was significantly lower in the patients compared with controls before PTK. Schirmer test results and goblet cell density did not show any significant alterations after PTK. CONCLUSIONS: Concurrent improvements in corneal sensitivity, tear film break up time, lipid layer interference grades, and conjunctival squamous metaplasia grades all point to the favorable effects of PTK on the ocular surface by improving the stability of the tear film and ocular surface health through attainment of a regular corneal surface and probably inducing qualitatively/quantitatively better mucin production by a healthier epithelium after PTK.

Adult↗

PubMed2000

Impact of sequential grafting of the internal thoracic or right gastroepiploic arteries on multiple coronary revascularization.

OBJECTIVE: The aim of the study is to clarify the efficacy of the sequential anastomotic technique of the arterial conduits for multiple coronary revascularization. BACKGROUND: The internal thoracic artery (ITA) is now widely accepted as a durable conduit for myocardial revascularization. The right gastroepiploic artery (GEA) has been developed as a third in situ arterial graft with an outcome similar to that of the ITA. MATERIAL AND METHOD: One hundred and forty five consecutive patients (116 male, 29 female, mean age 60.4yr) who received sequential grafting of either the ITA or GEA or both were retrospectively analysed. RESULTS: Sequential anastomoses were performed in 121 in situ left ITAs, 36 in situ GEAs and 12 composite right ITAs. No in situ right ITA was anastomosed sequentially. Two to six vessels (mean 3.8) were revascularized for each patient. Of the total 543 bypassed vessels, 432 (79.6%) were reconstructed with the arterial grafts. In 85 patients with quadruple bypass or more, the arterial grafts were able to reconstruct 266 out of 360 (74.0%) target vessels. Seventy one patients (49.0%) were revascularized without venous grafts. The arterial grafts could revascularize 293 out of 310 vessels (94.5%) in the LAD approximately Diagonal region, 83 out of 113 (73.4%) in the distal RCA or Cx region. There were no cardiac events responsible for the arterial grafts in the follow up period. CONCLUSION: In light of our experience, multiple revascularization with in situ arterial sequential grafts is feasible. Aggressive application of this technique provides patients requiring multiple coronary revascularization with favorable long-term results.

Abdomen↗

PubMed2000

RGD peptide-induced apoptosis in human leukemia HL-60 cells requires caspase-3 activation.

RGD motif-containing peptides have been used in various studies of cell adhesion and growth. We report that RGD triggered apoptosis at a concentration of 1 mmol/L, whereas RAD-containing peptides failed to induce apoptosis in HL-60 cells. RGD-treated cells revealed internucleosomal DNA fragmentation. Western blot reveals caspase-3 activation in RGD peptide-treated cells. A caspase-3 inhibitor z-VAD-FMK completely blocked the apoptosis, but a caspase-1 inhibitor (Ac-YVAD-CMK) and caspase-2 inhibitor (z-VDVAD-FMK) did not block the apoptosis, suggesting that caspase-3 might have a critical role in the execution process of apoptosis induced by RGD. RGD peptides have been used extensively to inhibit tumor metastasis. Our results should help in further understanding the RGD peptide-induced apoptosis, which is important since RGD peptides have a potential role in therapies of the future.

Amino Acid Chloromethyl Ketones↗

PubMed2000

Visual and tear function improvement after superficial phototherapeutic keratectomy (PTK) for mid-stromal corneal scarring.

PURPOSE: To study the changes in visual and tear film function following superficial excimer laser phototherapeutic keratectomy in patients with mid-stromal corneal scars. METHODS: Fourteen eyes of 14 patients with mid-stromal corneal scars seen at the Department of Ophthalmology at Kobe Kaisei Hospital underwent superficial phototherapeutic keratectomy (PTK). The subjects underwent routine ophthalmic examinations, corneal sensitivity measurements, tear film break-up time (BUT), Schrimer test and tear film lipid layer interferometry. Thirty eyes of 15 normal control subjects were also studied. The patients and the control subjects were compared for pre-PTK tear function parameters and tear film lipid layer interferometry grade. The alterations in these parameters within 6 months following PTK were also determined. RESULTS: Visual improvement was achieved in 12 eyes (86%). A hyperopic shift was observed in all eyes. The average pre-PTK corneal sensitivity and tear film BUT were lower in patients compared with control subjects before PTK. Tear film lipid layer interferometry grades were also higher in the patients than the controls before PTK. All these parameters improved gradually and significantly after PTK. Schirmer test results did not show any significant alterations after PTK. CONCLUSION: We conclude that PTK is an effective means of treating corneal scars and attaining visual improvement, even in cases with deeper corneal involvement, and may obviate the need for corneal transplantation. Simultaneous improvements in corneal sensitivity and tear film stability suggest favourable effects of PTK on the ocular surface.

Adult↗

PubMed2000

Indirect amperometric detection of underivatized amino acids in microcolumn liquid chromatography with carbon film based ring-disk electrodes.

An indirect amperometric detection of underivatized amino acids has been developed using a carbon film based ring-disk electrode (CFBRDE) in microcolumn liquid chromatography (LC). Bromide present in the mobile phase could be efficiently oxidized to bromine at the upstream (disk) electrode, and was subsequently detected at the downstream (ring) electrode. Most of the underivatized amino acids that are electroinactive under conventional amperometric conditions react rapidly with the electrogenerated bromine, the concentration of amino acids can therefore be indirectly determined by continuously monitoring the reduction current of bromine. The signal monitored at the downstream electrode was largely dependent on the bromide concentration in the mobile phase. Under optimized conditions, the response linearly increased with the concentration for most of the amino acids over a concentration range of 1-100 microM, with a correlation coefficient of 0.990-0.993. The detection limits for most of the amino acids were below 1 microM (0.2 pmol). It was demonstrated that detection with a ring-disk electrode offers the advantages of achieving a much higher collection efficiency caused by a decrease in flow rate in the microcolumn LC.

Amino Acids↗

PubMed2000

A novel approach with magnetic resonance imaging used for the detection of lung allograft rejection.

OBJECTIVE: Although various techniques have been explored for the detection and quantification of allograft transplant rejection, a practical and reliable method that is noninvasive is still elusive. METHODS: For our magnetic resonance imaging experiments, we have developed a new rat model of heterotopic lung transplantation to the inguinal region. Allogeneic transplants (DA to Brown Norway) were performed with and without cyclosporine A (INN: ciclosporin) treatment, with syngeneic transplants (Brown Norway to Brown Norway) serving as controls (n = 6 per group). Magnetic resonance images were obtained with a gradient echo method before and after injection of ultra-small superparamagnetic iron oxide particles. RESULTS: At day 5, allogeneic transplants without cyclosporine A treatment showed a grade 4 rejection histologically. A significantly lower magnetic resonance signal was seen 24 hours after injection of ultra-small superparamagnetic iron oxide particles compared with the preinjection image (346 +/- 7.6 vs 839 +/- 43.4 arbitrary units; P <. 05). Syngeneic transplants showed no evidence of rejection histologically and no differences in magnetic resonance imaging signals between the images before and after injection of ultra-small superparamagnetic iron oxide particles (863 +/- 18.8 vs 880 +/- 22.5). Allotransplants treated with cyclosporine A showed a grade 2 rejection histologically. The change in magnetic resonance signals in that group was small but showed a significant decrease in signal intensity after injection (646 +/- 10.5 vs 889 +/- 23.5, P <.05). Immunohistochemistry and iron staining of the allografts indicated that ultra-small superparamagnetic iron oxide particles were taken up by the infiltrating macrophages that accumulated at the rejection site. CONCLUSIONS: We have demonstrated a novel approach for the detection of acute lung allograft rejection using magnetic resonance imaging coupled with injection of ultra-small superparamagnetic iron oxide particles. Despite its limitations, our method might be a first step toward a potential clinical application.

Analysis of Variance↗

PubMed2000

Properties of two VEGF receptors, Flt-1 and KDR, in signal transduction.

The properties of two VEGF receptors, Flt-1 and KDR, in the signal transduction of VEGF in human umbilical vein endothelial cells (HUVECs) were investigated by using two newly developed blocking monoclonal antibodies (mAbs) against Flt-1 and KDR. VEGF stimulated the expression of transcription factor Ets-1 as well as matrix metalloproteinase-1 (MMP-1) and Flt-1 in HUVECs. The KDR/Flt-1 heterodimer and the KDR homodimer mediate the expression of Ets-1, MMP-1, and Flt-1. VEGF also stimulated DNA synthesis and migration of HUVECs. DNA synthesis is mediated by the same signaling system as the expression of Ets-1. In contrast, cell migration is regulated by two distinct signaling systems. The Flt-1 homodimer is required for actin reorganization. The KDR/Flt-1 heterodimer and the KDR homodimer are required for the assembly of vinculin in focal adhesion plaque by regulating the phosphorylation of focal adhesion kinase (FAK) and paxillin.

Endothelial Growth Factors↗

PubMed2000

Transcription of krox-20/egr-2 is upregulated after exposure to fibrous particles and adhesion in rat alveolar macrophages.

Alveolar macrophages meet various types of particulate substances deposited deep in the lung. We report differences in biologic responses of alveolar macrophages between phagocytosis of fine spherical and fibrous particles. Although titanium dioxide (TiO(2)) is thought to be biologically inert, the cytotoxicity of fibrous TiO(2) (F-TiO(2)) was much higher than spherical TiO(2) (S-TiO(2)). Differential display and the subsequent Northern blot analysis indicated that transcription of krox-20/egr-2 gene was slightly and greatly upregulated in S- and F-TiO(2)-exposed alveolar macrophages, respectively. The messenger RNA (mRNA) level of krox-20/egr-2 increased up to 8 h in F-TiO(2)-exposed alveolar macrophages, whereas krox-20/egr-2 mRNA level was transiently increased in response to adhesion to the culture dish. Stimulation with lipopolysaccharide also increased krox-20/egr-2 mRNA level transiently, although the mRNA level rebounded after 8 h. The analysis with 5' rapid amplification of complementary DNA ends suggested that there is a heterogeneity in the upstream region of this gene (krox-20/egr-2 and krox-20H1; accession numbers AB032420 and AB032419, respectively). The polymerase chain reaction analysis with specific primers for krox-20/egr-2 and krox-20H1 indicated that both genes were almost equally upregulated after either adhesion to the plastic dish or phagocytosis of F-TiO(2). These results suggest that both krox-20/egr-2 and krox-20H1 are implicated in adhesion and phagocytosis, and that the expression of krox-20 may reflect interaction with foreign substances and adhesion in alveolar macrophages.

5' Untranslated Regions↗

PubMed2000

Characterization of hydrogen peroxide-induced apoptosis in mouse primary cultured hepatocytes.

The influence of oxidative stress by hydrogen peroxide (H2O2) was examined in mouse primary cultured hepatocytes. A change in morphology was observed in hepatocytes incubated for 30 min in saline A containing H2O2. The percentage of dead cells, as measured by the fluorescence method, was increased in a dose-dependent manner. In addition, a ladder-like DNA fragmentation pattern was detected by agarose gel electrophoresis 1 h after exposure to 3 mM H2O2. This phenomenon was prolonged for 24 h. Hydrogen peroxide-induced cell viability reduction and DNA fragmentation were dose-dependently protected by the addition of antioxidants (N-acetylcysteine, L-ascorbic acid), a metal-chelator (1,10-phenanthroline), iron-chelator (deferoxamine) and intracellular calcium ion chelator (quin 2-AM). No influence, however, was detected by endonuclease inhibitors (zinc, aurintricarboxylic acid) and poly (ADP-ribose) polymerase inhibitors (3-aminobenzamide, theophylline). These results following H2O2-induced cell viability reduction suggested that oxidative stress by H2O2 itself or H2O2-derived changes involved in ferrous or intracellular calcium ions resulted in apoptosis in mouse primary cultured hepatocytes. These phenomena are not likely to be associated with endonuclease or poly (ADP-ribose) polymerase.

Acetylcysteine↗